This is a time server comparing to the standard Period_converter.mq4 which ships with the Metatrader. It converts 1 min bars to all MT4 standard time frames, i.e. 5m, 15m, 30m, 1h, 4h, 1d, 1w, 1mn in a single run. Therefore, instead of running the Period_converter 8 times you can run this script only once. This is particulary useful after importing 1 min data from a source like the Alpari databank.